Headliners for motor vehicles are mounted inside the passenger compartment and against the sheet metal roof of the vehicle to provide an aesthetic covering for the sheet metal. Conventionally, headliners were constructed of a single layer. More recently, headliners comprising multiple layers laminated together have been proposed.
U.S. Pat. No. 4,131,702, for example, describes a self-supporting molded headliner formed of a layered composite arrangement of polyethylene foam panels laminated on both sides to a reinforcing layer of rigid paperboard. Similarly, U.S. Pat. No. 5,503,903 shows a headliner including front and back sheets of wood fibers and polypropylene laminated with an intermediate corrugated sheet, while U.S. Pat. No. 4,020,207 shows a multiple-layer structure comprising two sheets of polyethylene foam bonded with a reinforcing polymer-containing layer.
Another known headliner construction includes top and bottom sheets attached together to form a duct in the rear portion of the headliner. The top sheet includes a corrugated cardboard layer sandwiched between two perforated polymer layers which allow moisture to pass therethrough. Furthermore, the top sheet is preformed by compression molding before being attached to the bottom sheet.
However, a need exists for a structural headliner in which a front-to-rear air duct is integrally formed, and a particular need exists for such a headliner having increased noise absorbing properties.